The deadly paris attacks that killed 129 people and wounded 352 more have sent shock waves across the world as many countries beefed up security and tightened checks on refugees.

The United States, widely accused of having a role in the turmoil in Syria, on Monday subjected Syrian refugees to the most intensive security checks of migrants.

"These refugees are subject to the highest level security checks of any category of traveler to the United States," State Department spokesman Mark Toner told a daily news briefing. "We think we can do this safely and in a way that reflects American values."

Also on Monday, several US governors threatened to stop accepting Syrian refugees as the attacks in Paris raised security worries over Syrian migrants amid concerns that terrorists might use the refugees as cover to sneak across borders.

One of the terrorists involved in Paris attacks was found to have a Syrian passport, and likely entered the country under the cover of refugees, according to French police.

The Pentagon announced on the same day that it would bolster intelligence sharing with the French military "to the fullest extent allowed by existing law and policy" over a range of shared challenges, said Pentagon spokesman Peter Cook.

Many European countries immediately announced tighter border controls after Friday's attacks in Paris. The moves by the Untied States, which has been reluctant to take Syrian refugees, sent another negative signal over the deteriorating refugee crisis.

Nevertheless, rampant attacks by the Islamic State (IS) militant group also highlighted the urgency to seek a political settlement of the Syrian crisis.

Russia, the United States and powers from Europe and the Middle East agreed in Vienna during the weekend on a timetable regarding the establishment of a transitional Syrian government and holding an election within 18 months.

They also agreed that fighting the IS is a priority in the course of achieving a political settlement in Syria.

The deadly attacks in Paris were deemed by experts as one of the reasons that pushed the international powers to reach a consensus on the need to prioritize the fight against terrorism.

"The mechanism of a political solution has become evident, and all of the voices now are directed towards the political solution," said Hasan Abdul-Azim, head of the National Coordination Body (NCB), the major political opposition force inside Syria.

Meanwhile, French President Francois Hollande announced that his country would intensify its operations in Syria following the French military's air strikes on Raqqa, Syria on Sunday night.

"We will continue the strikes in the coming weeks," he noted, adding that the Charles de Gaulle aircraft carrier would be deployed to the eastern Mediterranean, which would "triple our capacity of action."

In a similar move, France's allies in the Pentagon said on Monday the USS Harry S. Truman aircraft carrier had left for the Middle East in the latest deployment to assist the counter-terror campaign in the region.

According to the US daily The Hill, which mainly covers news of the US Congress, Truman would join the French aircraft carrier Charles de Gaulle, whose departure was scheduled for Nov. 18, in the Gulf region to assist the campaign against the IS in Iraq and Syria.